The overall objective of our study is to understand the manner in which fetal globin gene expression is repressed late in fetal development, and the basis for the concomitant initiation of adult globin gene expression. Our approach to this problem has been to clone the globin genes from goat, and to characterize their sequence organization. Our hope is that from such a study, clues concerning the mechanism of the globin switch will be found. Goats have been chosen for this study because they have a developmentally controlled switch in globin chains much the same as humans. Also, when adult goats are made anemic, they switch from the adult to a juvenile form of hemoglobin.